EX1 and EX2, and even Galaxy cellphones -- all have Sony's CMOS sensors..

It's only for APSC that Samsung chose to use their own sensors. The 20 MP sensor is good, but the 14 MP sensor in previous generation is the
main
reason why Samsung's NX system got sidelined. They lost more than an year due to the 14 MP sensor, and by the time they rolled out the 20 MP sensor, NX was already forgotten system.

Once you are behind it's pretty hard to pick up agaiin, as people have already invested in lenses and adapters etc. and they also recommend to friends and family the system they already own. That's why Canon and Nikon have a such a tight grip in DSLR market.